Why Strength Training Is Important for Endurance Athletes

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Strength Training for Endurance Athletes

The Strength With Which To Endure

It’s an open secret in the endurance athlete community that the most often-skipped portion of their programming is strength training.

After all, if I’m an endurance athlete, why would I want to “bulk up,” “become muscle-bound,” or otherwise shift my focus away from practicing the skills and conditioning of my particular sport?

Even in 2022 there is not enough awareness of the importance of strength training for endurance athletes, or its benefits.

The truth is that strength training as part of your endurance training program is essential, and there are many ways to accomplish this:


There are many reasons it is important, and we will touch on those and how you can train to complement the specific needs of your endurance races.

Tendon and Ligament Resilience for Endurance Athletes

Tendon and ligaments are what we need to perform well over time. In our recent blog post about the benefits of eccentric training, we pointed to this meta-analysis that discusses the “spring-like” characteristics of our connective tissues.

Specifically, the element of strength training for endurance athletes that has direct applications to sport performance is the nature of the muscle-tendon systems responsible for our movement, which function both as shock absorbers and springs.

Imagine a stride while running.

When the force exerted on the muscle (landing) exceeds the force developed by the muscle, work is done by the stretching muscle and it absorbs mechanical energy in the process—the active muscle lengthening in an eccentric contraction. What happens to that absorbed energy next depends on how the muscle is being used.

The energy can be dissipated as heat, in which case the muscle is functioning as a damper or shock absorber—like when you’re walking downhill—or it can be stored temporarily as elastic recoil potential energy and subsequently recovered and added to the force of the subsequent stride—like when you’re running.

So if a muscle is chronically subjected to heavy loads, does it respond with increased stiffness of this muscle spring? It sure does, and this “stiffer spring” can have two impacts:

First, it can act to protect the stretching muscle from stretch overload damage and reduce injury risk.

Second, a stiffer spring can enhance the amount of elastic recoil energy—or “springiness”— available in the stretch, increasing the power output and explosiveness of the ensuing stride without further taxing the body’s energy systems.

In other words, this is a structural improvement above and beyond the chemical/metabolic improvements seen in traditional training.

Reducing injury risk while improving performance? Strength training for endurance athletes may be better than originally imagined.

Endurance Athletes and Bone Density

Make no bones about it, the health of your skeleton is the often-overlooked foundation of any endurance training. After age twenty-five or so your bone density begins to decrease. Osteoporosis is now a global epidemic, typically caused by a lack of meaningful mechanical loading during exercise.

It’s now understood that mechanical loading is the primary stimulus for the growth and maintenance of bone density. Even strength training with traditional tools like weights can provoke this effect, while ARX optimizes it. But strength athletes who neglect this type of training cannot obtain this enhanced bone density in any other way.

Furthermore, it’s eccentric loading—mechanical loading as an active muscle lengthens—that is best for increasing bone mineral density.

There is no downside—and lots of upsides—to enhancing an endurance athlete’s bone density. And since this is only possible through strength training, a strength training plan for endurance athletes is unavoidably appropriate.

Additional Read: How To Build Your Bones For Life

An ARX Triathlete Case Study

Back in January of 2020, an amateur triathlete named Eric Anderson began using an ARX program for his strength training.

He runs The Ocean Lab here in Austin, a float therapy and infrared sauna facility that focuses on de-stressing and recovery. They bill themselves as “the most relaxing place in Austin,” and boy was he going to need it after his ARX workouts!

Eric was very consistent over the course of 2020 and into 2021, performing one weekly ARX workout lasting about fifteen minutes, a huge reduction when compared with the weekly time commitment often recommended for endurance athletes.

He experienced a doubling in strength of all major muscle groups within 4-6 months, and kept gradually increasing his strength from there.

He reports that during this time he—a seasoned athlete with years of consistent training under his belt—gained twelve pounds of muscle as a result of his ARX workouts. Adding weight might seem like a drawback for an endurance athlete, but the truth is actually the opposite.

ARX’s eccentric loading also recruits satellite cells to become new muscle tissue, hence his weight increase.

His training outside of ARX, though, was obviously focused on endurance and muscular work capacity. So the new muscle tissue that was being built was having a heavy demand placed on it for the performance of low-intensity, steady-state work that could be maintained for longer periods of time. And because the muscle tissue responds to imposed demands, the new muscle tissue experienced upgregulation of the enzymes involved in fuel metabolism.

In other words, the performance of the new muscle far outweighed—no pun intended—the negative of having the additional weight to move through a triathlon course.

Again, his total monthly exercise time on ARX was just over an hour per month, so he found it very easy to fit into his training schedule, his busy work schedule running his business, and his personal life. As you can imagine, triathletes are extremely busy logging hours each week, so it was imperative that his strength training be as brief and as effective as possible.

Here are some images he took to compare his physique before and after a few months of his ARX training program:

ARX Training-Before and After Photo
ARX Training-Before and After Photo

As you can imagine, he experienced performance gains in each phase of his endurance training.

He had:

  • Finally qualified for the Iron Man World Championships in Kona
  • Dropped his marathon time from 3:32 to 3:03
  • “Built himself a bigger engine” in the form of mitochondria-rich muscle tissue
  • Enhanced his bone density through repeated bouts of maximal eccentric loading
  • Increased the force-absorption capacity of his tendons and ligaments, as well as the magnitude of their “spring-like” rebound strength.

As a result of the success of his ARX program, the Ocean Lab will be adding ARX technology to their offerings in 2022. Not wanting to keep these types of results to himself, Eric is looking forward to helping his clients—competitive athletes and regular folk alike—experience a safer, more effective, and more efficient way to improve their body composition and function.

Additional Read: Gain More Muscle Mass in Less Time with Adaptive Resistance Training

What Are You Waiting For?

If you’re still not incorporating a strength training protocol into your endurance training program—or the programs of your athletes if you’re a coach—we’re not sure what to tell you.

It’s all upside and no downside. Not only does strength training offer improved performance through the enhancement of the connective tissues’ spring effect, but it also makes you more resistant to injury through the increase in bone density and connective tissue thickness/resilience.

And the great news is that it no longer requires 3-5 hours per week to incorporate this training. As seen in Mr. Anderson’s example, it can take as little as fifteen minutes of ARX once per week.

Welcome to the future of exercise!

ARX simplifies the most comprehensive full-body workout through perfectly matched, motorized resistance. Short for Adaptive Resistance Exercise, ARX is scientifically proven to deliver quantifiable results in less time. The all-in-one strength training machine dynamically adjusts resistance in real-time to personalize every workout. ARX empowers and challenges individuals to achieve their fitness goals one perfectly calibrated repetition at a time. No dangerous weights to drop and no adjustments to make, just exact resistance. Founded in 2016, ARX is headquartered in Austin, Texas.

For more information, please visit ARXFit.com and join the community on FacebookInstagram and YouTube.